1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Definitions for the IP router.
8 *
9 * Version: @(#)route.h 1.0.4 05/27/93
10 *
11 * Authors: Ross Biro
12 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
13 * Fixes:
14 * Alan Cox : Reformatted. Added ip_rt_local()
15 * Alan Cox : Support for TCP parameters.
16 * Alexey Kuznetsov: Major changes for new routing code.
17 * Mike McLagan : Routing by source
18 * Robert Olsson : Added rt_cache statistics
19 */
20#ifndef _ROUTE_H
21#define _ROUTE_H
22
23#include <net/dst.h>
24#include <net/inetpeer.h>
25#include <net/flow.h>
26#include <net/inet_sock.h>
27#include <net/ip_fib.h>
28#include <net/arp.h>
29#include <net/ndisc.h>
30#include <linux/in_route.h>
31#include <linux/rtnetlink.h>
32#include <linux/rcupdate.h>
33#include <linux/route.h>
34#include <linux/ip.h>
35#include <linux/cache.h>
36#include <linux/security.h>
37
38#define RTO_ONLINK 0x01
39
40static inline __u8 ip_sock_rt_scope(const struct sock *sk)
41{
42 if (sock_flag(sk, flag: SOCK_LOCALROUTE))
43 return RT_SCOPE_LINK;
44
45 return RT_SCOPE_UNIVERSE;
46}
47
48static inline __u8 ip_sock_rt_tos(const struct sock *sk)
49{
50 return RT_TOS(READ_ONCE(inet_sk(sk)->tos));
51}
52
53struct ip_tunnel_info;
54struct fib_nh;
55struct fib_info;
56struct uncached_list;
57struct rtable {
58 struct dst_entry dst;
59
60 int rt_genid;
61 unsigned int rt_flags;
62 __u16 rt_type;
63 __u8 rt_is_input;
64 __u8 rt_uses_gateway;
65
66 int rt_iif;
67
68 u8 rt_gw_family;
69 /* Info on neighbour */
70 union {
71 __be32 rt_gw4;
72 struct in6_addr rt_gw6;
73 };
74
75 /* Miscellaneous cached information */
76 u32 rt_mtu_locked:1,
77 rt_pmtu:31;
78};
79
80static inline bool rt_is_input_route(const struct rtable *rt)
81{
82 return rt->rt_is_input != 0;
83}
84
85static inline bool rt_is_output_route(const struct rtable *rt)
86{
87 return rt->rt_is_input == 0;
88}
89
90static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
91{
92 if (rt->rt_gw_family == AF_INET)
93 return rt->rt_gw4;
94 return daddr;
95}
96
97struct ip_rt_acct {
98 __u32 o_bytes;
99 __u32 o_packets;
100 __u32 i_bytes;
101 __u32 i_packets;
102};
103
104struct rt_cache_stat {
105 unsigned int in_slow_tot;
106 unsigned int in_slow_mc;
107 unsigned int in_no_route;
108 unsigned int in_brd;
109 unsigned int in_martian_dst;
110 unsigned int in_martian_src;
111 unsigned int out_slow_tot;
112 unsigned int out_slow_mc;
113};
114
115extern struct ip_rt_acct __percpu *ip_rt_acct;
116
117struct in_device;
118
119int ip_rt_init(void);
120void rt_cache_flush(struct net *net);
121void rt_flush_dev(struct net_device *dev);
122struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp,
123 const struct sk_buff *skb);
124struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp,
125 struct fib_result *res,
126 const struct sk_buff *skb);
127
128static inline struct rtable *__ip_route_output_key(struct net *net,
129 struct flowi4 *flp)
130{
131 return ip_route_output_key_hash(net, flp, NULL);
132}
133
134struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
135 const struct sock *sk);
136struct dst_entry *ipv4_blackhole_route(struct net *net,
137 struct dst_entry *dst_orig);
138
139static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
140{
141 return ip_route_output_flow(net, flp, NULL);
142}
143
144static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
145 __be32 saddr, u8 tos, int oif)
146{
147 struct flowi4 fl4 = {
148 .flowi4_oif = oif,
149 .flowi4_tos = tos,
150 .daddr = daddr,
151 .saddr = saddr,
152 };
153 return ip_route_output_key(net, flp: &fl4);
154}
155
156static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
157 const struct sock *sk,
158 __be32 daddr, __be32 saddr,
159 __be16 dport, __be16 sport,
160 __u8 proto, __u8 tos, int oif)
161{
162 flowi4_init_output(fl4, oif, mark: sk ? READ_ONCE(sk->sk_mark) : 0, tos,
163 scope: sk ? ip_sock_rt_scope(sk) : RT_SCOPE_UNIVERSE,
164 proto, flags: sk ? inet_sk_flowi_flags(sk) : 0,
165 daddr, saddr, dport, sport, uid: sock_net_uid(net, sk));
166 if (sk)
167 security_sk_classify_flow(sk, flic: flowi4_to_flowi_common(fl4));
168 return ip_route_output_flow(net, flp: fl4, sk);
169}
170
171static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
172 __be32 daddr, __be32 saddr,
173 __be32 gre_key, __u8 tos, int oif)
174{
175 memset(fl4, 0, sizeof(*fl4));
176 fl4->flowi4_oif = oif;
177 fl4->daddr = daddr;
178 fl4->saddr = saddr;
179 fl4->flowi4_tos = tos;
180 fl4->flowi4_proto = IPPROTO_GRE;
181 fl4->fl4_gre_key = gre_key;
182 return ip_route_output_key(net, flp: fl4);
183}
184int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
185 u8 tos, struct net_device *dev,
186 struct in_device *in_dev, u32 *itag);
187int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
188 u8 tos, struct net_device *devin);
189int ip_route_use_hint(struct sk_buff *skb, __be32 dst, __be32 src,
190 u8 tos, struct net_device *devin,
191 const struct sk_buff *hint);
192
193static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
194 u8 tos, struct net_device *devin)
195{
196 int err;
197
198 rcu_read_lock();
199 err = ip_route_input_noref(skb, dst, src, tos, devin);
200 if (!err) {
201 skb_dst_force(skb);
202 if (!skb_dst(skb))
203 err = -EINVAL;
204 }
205 rcu_read_unlock();
206
207 return err;
208}
209
210void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
211 u8 protocol);
212void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
213void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol);
214void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
215void ip_rt_send_redirect(struct sk_buff *skb);
216
217unsigned int inet_addr_type(struct net *net, __be32 addr);
218unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
219unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
220 __be32 addr);
221unsigned int inet_addr_type_dev_table(struct net *net,
222 const struct net_device *dev,
223 __be32 addr);
224void ip_rt_multicast_event(struct in_device *);
225int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
226void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
227struct rtable *rt_dst_alloc(struct net_device *dev,
228 unsigned int flags, u16 type, bool noxfrm);
229struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt);
230
231struct in_ifaddr;
232void fib_add_ifaddr(struct in_ifaddr *);
233void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
234void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric);
235
236void rt_add_uncached_list(struct rtable *rt);
237void rt_del_uncached_list(struct rtable *rt);
238
239int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
240 u32 table_id, struct fib_info *fi,
241 int *fa_index, int fa_start, unsigned int flags);
242
243static inline void ip_rt_put(struct rtable *rt)
244{
245 /* dst_release() accepts a NULL parameter.
246 * We rely on dst being first structure in struct rtable
247 */
248 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
249 dst_release(dst: &rt->dst);
250}
251
252#define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3)
253
254extern const __u8 ip_tos2prio[16];
255
256static inline char rt_tos2priority(u8 tos)
257{
258 return ip_tos2prio[IPTOS_TOS(tos)>>1];
259}
260
261/* ip_route_connect() and ip_route_newports() work in tandem whilst
262 * binding a socket for a new outgoing connection.
263 *
264 * In order to use IPSEC properly, we must, in the end, have a
265 * route that was looked up using all available keys including source
266 * and destination ports.
267 *
268 * However, if a source port needs to be allocated (the user specified
269 * a wildcard source port) we need to obtain addressing information
270 * in order to perform that allocation.
271 *
272 * So ip_route_connect() looks up a route using wildcarded source and
273 * destination ports in the key, simply so that we can get a pair of
274 * addresses to use for port allocation.
275 *
276 * Later, once the ports are allocated, ip_route_newports() will make
277 * another route lookup if needed to make sure we catch any IPSEC
278 * rules keyed on the port information.
279 *
280 * The callers allocate the flow key on their stack, and must pass in
281 * the same flowi4 object to both the ip_route_connect() and the
282 * ip_route_newports() calls.
283 */
284
285static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst,
286 __be32 src, int oif, u8 protocol,
287 __be16 sport, __be16 dport,
288 const struct sock *sk)
289{
290 __u8 flow_flags = 0;
291
292 if (inet_test_bit(TRANSPARENT, sk))
293 flow_flags |= FLOWI_FLAG_ANYSRC;
294
295 flowi4_init_output(fl4, oif, READ_ONCE(sk->sk_mark), tos: ip_sock_rt_tos(sk),
296 scope: ip_sock_rt_scope(sk), proto: protocol, flags: flow_flags, daddr: dst,
297 saddr: src, dport, sport, uid: sk->sk_uid);
298}
299
300static inline struct rtable *ip_route_connect(struct flowi4 *fl4, __be32 dst,
301 __be32 src, int oif, u8 protocol,
302 __be16 sport, __be16 dport,
303 const struct sock *sk)
304{
305 struct net *net = sock_net(sk);
306 struct rtable *rt;
307
308 ip_route_connect_init(fl4, dst, src, oif, protocol, sport, dport, sk);
309
310 if (!dst || !src) {
311 rt = __ip_route_output_key(net, flp: fl4);
312 if (IS_ERR(ptr: rt))
313 return rt;
314 ip_rt_put(rt);
315 flowi4_update_output(fl4, oif, daddr: fl4->daddr, saddr: fl4->saddr);
316 }
317 security_sk_classify_flow(sk, flic: flowi4_to_flowi_common(fl4));
318 return ip_route_output_flow(net, flp: fl4, sk);
319}
320
321static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
322 __be16 orig_sport, __be16 orig_dport,
323 __be16 sport, __be16 dport,
324 const struct sock *sk)
325{
326 if (sport != orig_sport || dport != orig_dport) {
327 fl4->fl4_dport = dport;
328 fl4->fl4_sport = sport;
329 ip_rt_put(rt);
330 flowi4_update_output(fl4, oif: sk->sk_bound_dev_if, daddr: fl4->daddr,
331 saddr: fl4->saddr);
332 security_sk_classify_flow(sk, flic: flowi4_to_flowi_common(fl4));
333 return ip_route_output_flow(sock_net(sk), flp: fl4, sk);
334 }
335 return rt;
336}
337
338static inline int inet_iif(const struct sk_buff *skb)
339{
340 struct rtable *rt = skb_rtable(skb);
341
342 if (rt && rt->rt_iif)
343 return rt->rt_iif;
344
345 return skb->skb_iif;
346}
347
348static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
349{
350 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
351 struct net *net = dev_net(dev: dst->dev);
352
353 if (hoplimit == 0)
354 hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl);
355 return hoplimit;
356}
357
358static inline struct neighbour *ip_neigh_gw4(struct net_device *dev,
359 __be32 daddr)
360{
361 struct neighbour *neigh;
362
363 neigh = __ipv4_neigh_lookup_noref(dev, key: (__force u32)daddr);
364 if (unlikely(!neigh))
365 neigh = __neigh_create(tbl: &arp_tbl, pkey: &daddr, dev, want_ref: false);
366
367 return neigh;
368}
369
370static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt,
371 struct sk_buff *skb,
372 bool *is_v6gw)
373{
374 struct net_device *dev = rt->dst.dev;
375 struct neighbour *neigh;
376
377 if (likely(rt->rt_gw_family == AF_INET)) {
378 neigh = ip_neigh_gw4(dev, daddr: rt->rt_gw4);
379 } else if (rt->rt_gw_family == AF_INET6) {
380 neigh = ip_neigh_gw6(dev, addr: &rt->rt_gw6);
381 *is_v6gw = true;
382 } else {
383 neigh = ip_neigh_gw4(dev, daddr: ip_hdr(skb)->daddr);
384 }
385 return neigh;
386}
387
388#endif /* _ROUTE_H */
389

source code of linux/include/net/route.h